The proposed Mentored Research Scientist Development Award (K01) will provide Dr. Mulawa with the training and mentorship to become an independent behavioral scientist focused on the development and evaluation of innovative multi-level interventions that reduce AIDS-related morbidity and mortality in resource- limited settings. The objective of the proposed research is to identify social network-level factors associated with adherence to antiretroviral therapy (ART) among perinatally HIV-infected adolescents in Cape Town, South Africa, and to use this information to develop and pilot test a mobile health (mHealth) intervention to promote ART adherence by engaging the social networks of this population. This K01 will provide the necessary support for Dr. Mulawa to achieve the following scientific training objectives: (1) obtain investigator- level skills in the design, execution, and evaluation of clinical trials, (2) build expertise in mHealth intervention development, deployment, and evaluation, (3) enrich statistical capacities in the analysis of egocentric and longitudinal social network data, and (4) gain proficiency in adolescent-specific theories of behavior change and concepts with salience to the South African cultural context. Additional professional training objectives include expanding training in the ethical conduct of cross-cultural research in low-resource settings and building general professional development skills. To support these goals, Dr. Mulawa has a mentoring team led by Dr. Kathleen Sikkema, an expert in the development and evaluation of HIV behavioral trials in the South African context. Co-Mentors and Advisors will provide expertise in the development of HIV-related mHealth interventions for adolescents (Dr. Lisa Hightow-Weidman), the use of social network analysis to understand adolescent behaviors (Dr. James Moody), adolescent psychiatric health in South Africa (Dr. Jacqueline Hoare), as well as quantitative (Dr. Joseph Egger) and qualitative methods (Dr. Melissa Watt). Training objectives will be met through a comprehensive training plan involving one-on-one meetings, didactics/trainings, mentor- directed readings, seminars/lab meetings, and scientific meetings. Skills gained through the training plan will be put into action through the execution of a complementary research plan. The proposed study will be conducted with a cohort of perinatally HIV-infected adolescents, ages 12-14 years in Aim 1 data, enrolled in a sub-study of the Cape Town Adolescent Antiretroviral Cohort (CTAAC). Aim 1 is to analyze egocentric social network data from CTAAC participants (n = 100) to identify the relationship between social network-level factors (structural and functional characteristics) and ART adherence. Aim 2 is to iteratively customize an mHealth intervention that leverages social networks to promote ART adherence in this population. Aim 3 is to pilot test the mHealth intervention with 50 CTAAC adolescents to a) assess its feasibility and acceptability and b) explore preliminary effects on ART adherence and social support. The proposed study will provide data for Dr. Mulawa?s first R01 proposal, to be submitted in the final year of this proposed award.